Within sprint cycling, the ankle’s primary role is transferring power generated at the hip and knee. However, a stiffer musculotendinous unit around the ankle may directly contribute to increased performance. The aim of this study was to measure the influence of isometric and plyometric training on ankle stiffness and sprint cycling performance. Fifteen international age-group sprint track cyclists completed a 10-week intervention. An experimental group (n = 8) performed high-volume plyometrics and isometric calf raises in addition to their normal training, whilst a control group (n = 7) continued with no intervention. Kinetic measures were recorded on a force plate and in sprints on an isokinetic ergometer at 60 and 135 rev/min. Kinematic measures were recorded using highspeed cameras and reflective markers. Isometric peak force during plantar flexion and vertical ankle stiffness when hopping were both increased in the intervention group (p ≤ 0.05). Bicycle sprints showed group differences in ankle stiffness (p = 0.01) at 135 rev/min and average ankle angle (p = 0.04) at 60 rev/min. Therefore, combined plyometrics and isometrics were an effective method for increasing ankle stiffness. This combination of stimuli also effected the utilisation of the ankle in sprint cycling.